Pilot seat ejector for aircraft



Dec. 25, 1951 o, LOBELLE 2,579,683

PILOT SEAT EJECTOR FOR AIRCRAFT Filed July 22, 1949 4 Sheets-Sheet 1 FIG. 1;

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I 1 /04 II I 9 I i 97 I Inventor Marce! (lOL bQl/Q Attorneys Dec. 25, 1951 M. J. o. LOBELLE 2,579,683

PILOT SEAT EJECTOR FOR AIRCRAFT Filed July 22, 1949 4 Sheets-Sheet 2 Inventor 0' Attorney S Dec. 25, 1951 M. J. o. LOBELLE PILOT SEAT EJECTOR FOR AIRCRAFT Filed July 22, 1949 4 Sheets-Sheet 3 k r e c M I) J Attorneys Inventor Pia TC? dQLobeHg 4 m 9 l w 0 Q L w 7 n ww 4. G F

Dec. 25, 1951 M. J.'o. LOBELLE 2,579,633

r PILOT SEAT EJECTOR FOR AIRCRAFT Filed July 22, 1949 4 Sheets-Sheet 4 V l 7 93 I/8 ir9nt7flllfl /O8 94 In 54 no en lor mla. QLQbeHe y W 4 Attorneys Patented Dec. 25, 1951 PILOT SEAT EJECTOR FOR AIRCRAFT Marcel Jules Odilon Lobelle, White Waltham, Maidenhead, England, assignor to Messrs. M. L. Aviation Company Limited, White Waltham, Maidenhead, England, a. British company Application July 22 1949, Serial No. 106,153 In Great Britain July 26, 1948 8 Claims.

This invention relates to seat ejection apparatus for the pilots and other occupants of aircraft of the kind in which the seat is adapted to be ejected through an opening in the aircraft by the pneumatic pressure of an explosive charge.

The invention is concerned particularly with seat ejection apparatus of the type described in British Patent specification No. 590,253, in which a pilots seat is mounted by means of guide members in the aircraft so that it can slide in an upward direction under the influence of an ejecting device comprising telescopic cylinders adapted to hold an explosive charge, While a locking device adapted normally to secure the seat in its working position is arranged to be released automatically by the gas pressure resulting from the explosion of the charge.

The object of the present invention is to provide a construction of ejecting device in which the risk of accidental firing of the cartridge is minimised and in which the consequences of accidental firing are rendered harmless.

The invention is illustrated by way of example in the accompanying drawings, of which:

Figure 1 is a side elevation of an ejectable seat installed in an aircraft.

Figure 2 is a shortened front view on an enlarged scale of the seat ejecting mechanism looking aft, with the seat removed from its supporting channels;

Figure 3 is a plan view of Figure 2;

Figure 4 is an elevation partly in section of the swinging breech mechanism seen from the front;

Figure 5 is a section on the line VV of Figure 4;

Figure 6 is a rear view, partly broken away, of the swinging breech mechanism;

Figure 7 is a central transverse section of the top of the breech with the breech head open and correctly arranged for loading;

Figure 8 is a similar view to Figure 7 but shows the operation of the safety latch when the breech head is incorrectly arranged;

Figure 9 is an enlarged sectional view of part of the swinging breech mechanism on the line IX-IXinFigure 2, and

Figure 10 is a central sectional view of the upper part of the breech on the line X-X in Figure 2.

The ejectable seat is installed in the cabin of an aircraft beneath a displaceable canopy II which can be jettisoned by known means during an emergency so that the pilot I 2 in his seat l3 can be ejected without interference through the opening formed between the front l4 and rear I6 fixed panels fore and aft of the canopy ll.

The seat structure is mounted at the rear on a pair of channels I! (see Figures 2 and 3) which are adapted to slide on rearwardly inclined lower and upper pairs of guide rails l8 and I9, which are fixed to the floor of the aircraft by means of brackets 22. The lower and upper guide rails l8 and I9 together form an integral structure, the lower rails l8 having an I-shaped section forming guides for lower pairs of rollers 23 mounted on the channels I], and the upper guide rails l9 also having an I-shaped section forming guides for pairs of upper rollers 24 mounted on the channels l1.

"his staggered arrangement of guide rails and rollers serves to sustain any torsional loading imposed on the seat back and yet permits the rollers 23 to leave the rails l8, and the rollers 24 to leave the rails I 9 simultaneously.

The installation also includes a protective apron 26 attached to the pilots head rest 21, the apron being of known type in which the front is carried by radius arms 28 which can turn on pivots 29 when pulled forward and downward by the handle grips 3|.

As Will be later described the pulling down of the apron Z6 is made to operate the e ection apparatus, and for this purpose a lever 32, fast with one of the arms 2-8, operates through a connecting rod 33, a bell-crank lever 34 and link 36, on the operating lever 31, shown in Figures 2, 4 and 6. The seat is arranged to be ejected by detonating an explosive charge, from which the products of combustion enter telescopic cylinders mounted-between the rails after the manner described in British patent specification No. 590,253.

As shown in Figure 2 the inner telescopic cyl- 1 inder 38 is mounted at its lower end on a, bracket 39, which is carried on rails l8 which are attached to the aircraft structure, while the outer telescopic cylinder 42 is fixed in a cylinder head 43 attached to the seat back via channels l1. These two cylinders are termed the reaction cylinder and the ejection cylinder, respectively. As shown in Figures 1 and 2 the bracket 39 normally rests on an aileron control tube 4| which passes beneath the pilots seat. A fiange B4 on the bottom of the outer or ejection cylinde 62 is normally held by a pair of claws 46, mounted by pivots 47 on the bracket 39, these claws being held together by means of a shear pin 48. The claws 46 are releasable upon detonation of the explosive charge by a piston 49 mounted within the inner or reaction cylinder 38. This piston 49 carries a saddle 5! on the end of its stem 52 which rests against oblique cam faces 53 formed on the claws, so that under pressure of the explosive charge on the piston 49, the saddle 5| forces the claws 45 apart, shearing the pin 48 and releasing the flange 44 on the outer cylinder 42.

Referring to Figures 2, 4, and 6, the explosive charge iscarried by a breech tube 54 having trunnions 56 which are supported by bearing bushes 51 in a bearing block 58. The bearing block 58 is attached to the seat back via chan nels I? but it is also fixed to the cylinder head 43 by means of cheek plates 59 and GI. The mouth 62 of the breech tube 54 has a cylindrically curved surface which works over a correspondingly curved concave surface 63 on the breech head, while a curved lip 64 on each side ofthe breech mouth engages slidably beneath an undercut at the bottom of each of the cheek plates 59v and SI (see Figure 9).

A central opening 66 in the cylinder headopen's directly into the ejection cylinder space, and to one side of the cylinder head 43 there is another port's! which communicates directly with an exhaust tube 68 fixed at its upper end in the cylinder head, and extending at its lower end slidably into a collar 69 (see Figure 2) where it terminates in communication with the atmosphere.

Except in cases of emergency, the breech tube 54 is maintained in communication with the exhaust tube .68, and pressing up against a. leaf spring II on the cylinder head by toggle links I2 and 13. This toggle is maintained slightly over centre between a cross. pin 14 mounted in the cheek plates 59, BI, and a pivot I6 which is carried by a lug 'I'I projecting from the side of the breech tube. 54, (see Figures 4 and 6) The toggle link I2 carries. a stud I3, which, in the over-centre position of the toggle, rests in a notch formed in the side of a slide bar I9, which is slidably mounted in, the cheek plate 6I. This slide bar I9 works in a, groove 8| cut on the inside face of the cheek plate BI, and it is maintained in the groove by studs 82 which project through a slot 83 in the cheek plate GI into a bracket 84 which slide over the outer face. of the. cheek .plate BI. This bracket 84 has a side lug 86. which carries an actuating rod 81, the actuating rod being guided in the upper part through a cleat 88 attached to the bearing block 58. The actuating rod 81 is in turn connected through a pin;89, and slot 9 I, coupling with the actuating lever 31 previously referred to, this actuating lever being .pivoted on a screw 92 fixed in the cheek plate BI. I

In the safe position of the breech tube 54 wherev it is in communication with the, exhaust tube 58 the slide bar 79 has its lower stud 82. resting at the bottom ofthe slot 83, while the link 33 and the end of the actuating lever 31 to which it is attached are fully raised, corresponding to the retracted position of, the protective apron 26. Pulling down the protective apron, will consequently raise the slide bar I9 and collapse the toggle links I2, I3, by the action of, the notch in the slide bar I9 on the stud 13 on the toggle link I2. As the slide bar 79 continues to rise the stud I8 rides out of the notch, and the side of the slide bar I9 locks the toggle in the collapsed position with the breech tube 54 turned into the firing position, during the continued upward movement of the slide bar and actuating rod 81.

The manner in which the further upward move-- ment of the actuating rod 81 is utilised to :fire the cartridge will now be described. 7

The firing mechanism, (see particularly Figures 6, '7 and is mounted on a breech block 93 which is pivotally mounted on a pin 94 held ina fork on one side of the breech head 96, which is integral with breech tube 54. The top of the 4 breech tube 54 is formed with a recess 91 in which the rim of the cartridge fits so that it lies flush with the surface of the breech head 96. On the opposite side of the breech block 93 from the pivot. 94, there, i'sa lug with a hole 93 which will register with similar holes 99 in the sides of the breech head 96 through which a fixing pin II can be inserted to secure the breech block 93 over thebase of "the cartridge. A tell-tale indicator consisting of a plunger I02 is mounted in the breech, block 93 with its stem I03 passing downward through a retaining nut I04 adjacent the recess 91 in the breech tube 54. A spring I09 is interposed to press the plunger I92 down towards the recess, so that the elevation of the plunger I02 will indicate whether or not the breech tube 544s loaded with a cartridge. A striker arm I0! is mounted on a pivot I08 in the breech block 93 and-this striker arm carries a firing pin I99 which is located centrally above the detonator cap of the cartridge when the breech block is closed, the breech block 93 having a central aperture ;I I I through Which the firing pin I09 may strike. The striker arm I07 carries also a pack of leaf springs II2 which are secured by a nut II3 on the shank II4 of the firing pin I09, and also by nuts H5 which are screwed on studs IIB projecting from the striker arm I01 (see Figure 10). An abutment roller'I I1 is mounted on an upward projection II8 from the breech head against which roller I H the spring pack H2 is flexed when the breech block 93 is closed, as in Figures 2, 4 and 6. The outer end of the striker arm I0? is held from turning inwards by a roller I33 mounted on the firing arm I20. The side of the firing arm I20 remote from the roller I I1 is forked around a lug on the breech block 93 to which it is hinged by means of a pin I I9. A trip lever I2I integral with the firing arm I20 (see Figures 2, 4 and 8) is disposed so that when the breech tube 54 is vertical, the outer end of the trip lever I2I lies in the path of a cross pin I22 in the head of the actuating rod 81. The cross pin I22 does not raise the trip lever I'2I until the breech tube 54 is locked and registered with the ejection cylinders.

The upward motion of the actuating rod 81 turns the firing. arm I20 about its pivot I I9, thus raising the striker arm'I0'I so that the flexural load on the spring pack H2 is increased. Ultimately the roller I38 will trip ast the outer edge of the striker arm I01, allowing this to spring back and fire the cartridge.

To prevent the escape ofexplosion gases at the joint between the breech tube 54 and the cylinder head 43, the mouth-of the breech tube is counterbored to receive a=sealing sleeve I23 (see Figure 9:) This sea-ling sleeve I23 has a central opening I24 which is normally closed by a diaphragm I25. The diaphragm is strong enough to withstand the initial pressure developed, for the purpose of sliding the sleeve I23 downwardso that the lower part enters a recess I26 formed in the concave surface 63 of the cylinder head 43. The above sleeve I23 first presses against the bottom of therecess I25 to form an effective seal against the cylinder head 43, while its rear edge I2? is feathered toprovide an effective seal Within the breech tube 54. With this achieved, the diaphragm I25 will collapse under the increasing pressure of the explosion and admit the explosion gases to the ejection and reaction cylinders.

A safety device is incorporated in the breech block 93 to prevent the fixing pin 10 I for the breech block 93 being inserted unless 'the'firin'garm I20. is placed with its roller I38. lying underneath the striker arm I01. For this purpose a latch arm I28 is carried by the pivot I08 on the breech block 93, the latch arm I28 having an arm portion I3I extending across the breech block underneath the striker arm I01, and a latch portion I32 extending downward in proximity with the fixing hole 99 in the breech head 96. A plate spring I33 fixed to the breech block 93 presses under the tip of the arm HI and when theroller I38 lies under the striker arm [01 on the firing arm I20, it will press down on the arm I3I to lie flat against the upper surface of the breech block 93, as shown in Figure 7. When the breech block 83 is closed on the breech head 95 so that the latch portion I32 is concentric with the fixing hole 98 in the breech block 93, this allows the fixing pin IIJI to be inserted.

If, however, the breech block 93 is lowered, as in Figure 8 with the roller I38 above the striker arm ID], the spring I33 partly raises the arm I3I so that the latch I32 interferes with the insertion of the fixing pin IOI.

This lever is shaped to engage on both sides of the actuating lever 31 under spring pressure and prevent the lever 31 from turning on its pivot 92. When, however, the seat is moved back into the correct position of installation for ejection, the tip of the lever I34 is pressed back by a cross bar I39 or other member of the seat structure so that the slotted arm 13! is turned out of engagement with the actuating lever 3'! to permit the latter to be operated.

I claim:

1. Seat ejection apparatus for aircraft comprising guide means fixed in the aircraft, an ejectable seat mounted in said guide means, an ejection cylinder attached to said seat, a reaction cylinder mounted on said guide means, one of said cylinders being mounted slidably within the other, an exhaust tube fixed on said ejection cylinder, a movable breech for said ejection cylinder, said breech having a tube adapted to hold an explosive charge, firing mechanism mounted on said breech, and actuating means adapted to move said breech from a safe position where it is in communication with said exhaust tube into the firing position where it is in communication with said ejection cylinder, said actuacting means being also adapted to operate the firing mechanism only when said breech is in the firing position.

2. Seat ejection apparatus according to claim 1, wherein the actuating means comprises toggle mechanism connected to said breech tube, a locking device adapted to secure said toggle mechanism when the breech tube is in the firing position, and a single actuating element adapted to operate said toggle mechanism, said locking device and the firing mechanism in sequence.

3. Seat ejection apparatus according to claim 1, wherein the firing mechanism comprises a breech block hinged to said breech tube, fixing means adapted to secure said breech block to said breech tube, said breech block bein adapted to close on and secure an explosive cartridge in said breech tube, a striker arm hinged to said breech block, resilient means adapted to load said striker arm, said resilient means being rendered operative upon closure of said breech block, and a firing arm pivoted to said breech block, said firing arm being adapted to trip said striker arm when turned on its pivot by said actuating element. 1

4. Seat ejection apparatus according to claim 3, wherein said firing means comprises a firing pin, cooperatingapertures in said breech block and breech tube adapted to receive said fixing pin, and a movable safety latch disposed in cooperativeen g agement with said firing arm, said safety latch being adapted to obstruct said apertures except when the firin arm is set to trip said striker arm. Y

5. Seat ejection apparatus for aircraft comprising guide means fixed in-the aircraft; an ejectable seat mounted in said guide means, an ejection cylinder attached to said seat, a reaction cylinder mounted on said guide means, one of said cylinders being mounted slidably within the other, an exhaust tube attached to said seat, a cylinder head fixed to said ejection cylinder and to said exhaust tube, a curved surface on said cylinder head formed with a port opening into said ejection cylinder and another port opening into said exhaust tube, a breech tube mounted pivotally on said seat, said breech tube being adapted to hold an explosive charge, firing mechanism mounted on said breech tube, and actuating means adapted to turn said breech tube from a safe position where the mouth of said breech tube opens into the exhaust port in said cylinder head, to a firing position where it opens into the cylinder port, said actuating means being adapted to operate the firing mechanism only when said breech tube is in the firing position.

6. Seat ejection apparatus according to claim 5, comprising also a sealing sleeve slidably mounted in the mouth of said breech tube, a perforatable closure in said sealing sleeve adapted to withstand the initial pressure of the explosive charge, and wherein a recess is formed around the cylinder port in the curved surface of said cylinder head, said recess being adapted to receive said sleeve and to cooperate therewith in forming a gas seal between said beech tube and said cylinder head.

'7. Seat ejection apparatus according to claim 5, wherein a curved lip is provided on each side of the mouth of said breech tube, while the cylinder head is provided with curved stop surfaces, said stop surfaces being slidably engaged by said curved lips and adapted to retain said breech tube thereby against the reaction thrust due to combustion of said explosive charge.

8. Seat ejection apparatus for aircraft comprising in combination guide means fixed in the aircraft, an ejectable seat mounted in said guide means, a protective apron device fixed to said seat, said apron being arranged to be pulled down over the face of an airman seated in the seat, an ejection cylinder attached to said seat, a reaction cylinder mounted on said guide means, one of said cylinders being mounted slidably within the other, an exhaust tube fixed on said ejection cylinder, a movable breech for said ejection cylinder, said breech being adapted to hold an explosive charge, firing mechanism mounted on said breech, and actuating means arranged to move said breech from a safe position where it is in communication with said exhaust tube into the firin position where it is in com.- munication with said ejection cylinder, said actuating means being operatively connected with said protective apron device for operation thereby, and being also adapted to operate the firing mechanism only when said breech is in the firing position.

MARCEL JULES ODILON LOBEILE.

(References on following page) '7 REFERENCES 01mm) The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 'Date 23,224 Barber et a1 'Mar. 15, 1 859 37,048 Milbagnk -'Dec.'2, 1862 Townsley Apr. 20. '1920 Number Name Date Barr May 11, 1920 Curriston Oct. 12, 1943 Bowers Nov. 30, 1943 Martin Apr. 19, 1949 FOREIGN PATENTS Country Date Great Britain Oct. '29, 1946 

